The long term goal is the development of a practical, single-dose, oral, cholera vaccine for use in both industrialized and developing countries. The specific aims are to utilize the strain Peru 15, an attenuated El Tor, V. Cholerae 01, which has already proven to be safe, immunogenic and efficacious, and to develop a formulation of this vaccine strain which will be sufficiently stable for wide-scale production and distribution. Live attenuated cholera vaccines will be most useful if they can be prepared inexpensively, and distributed with minimal need for a cold chain. While newly developed killed and attenuated oral cholera vaccines are being licensed in Europe, both of these, as currently formulated, will be too expensive for use in cholera endemic regions because of their high production cost and their continued need for a cold chain. The proposed research will examine new ways of bacterial growth and preservation which could make the vaccine practical and inexpensive. Specifically, the study will evaluate new bacteriological media, alternative fermentation technologies, and improvements in lyophilization procedures, as well as evaluation of liquid formulations. Each of the conditions will be evaluated with the view toward procedures which could be adapted to GMP conditions and to vaccine producers in developing countries. The unique aspect of this work is the adaptation of this high tech genetically engineered strain of procedures which will make this vaccine available in geographic areas where it is needed.